Citation
Steeghs, N. (2009, November 24). Targeted therapy in oncology:
mechanisms and toxicity. Retrieved from https://hdl.handle.net/1887/14431
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6
Hypertension and rarefaction during treatment with telatinib, a small molecule angiogenesis inhibitor
Neeltje Steeghs,1,3 Hans Gelderblom,1 Jos op ’t Roodt,2 Olaf Christensen,5 Prabhu Rajagopalan,5
Marcel Hovens,3 Hein Putter,4 Ton J. Rabelink,2 Eelco de Koning2
1Departments of Clinical Oncology, 2Nephrology, 3General Internal Medicine, and 4Medical Sta- tistics and Bioinformatics, Leiden University Medical Center, Leiden,The Netherlands and 5Depart- ment of Clinical Pharmacology, Bayer Pharmaceuticals Corporation, WestHaven, Connecticut, USA.
Clin Cancer Res 2008 Jun 1;14(11):3470-6
Abstract
Purpose
Hypertension is a commonly reported side effect in antiangiogenic therapy. We inves- tigated the hypothesis that telatinib, a small molecule angiogenesis inhibitor, impairs vascular function, induces rarefaction, and causes hypertension.
Experimental Design
A side-study was done in a phase I trial of telatinib, a small molecule tyrosine kinase in- hibitor of vascular endothelial growth factor receptors 2 and 3, platelet-derived growth factor receptor, and c-KIT in patientswith advanced solid tumors. Measurements of blood pressure, flow-mediated dilation, nitroglycerin-mediated dilation, aortic pulse wave ve- locity, skin blood flux with laser Doppler flow, and capillary density with sidestream dark field imaging were done at baseline and after 5 weeks of treatment. Blood pressure and proteinuria were measured weekly.
Results
Mean systolic and diastolic blood pressure values increased significantly at +6.6mmHg (P = 0.009) and +4.7 mm Hg (P = 0.016), respectively. Mean flow-mediated dilation and mean nitroglycerin-mediated dilation values significantly decreased by -2.1% (P = 0.003) and -5.1% (P = 0.001), respectively. After 5 weeks of treatment, mean pulse wave velocity significantly increased by 1.2 m/s (P = 0.001). A statistically significant reduc- tion of mean skin blood flux of 532.8% arbitrary units was seen (P=0.015). Capillary density statistically significantly decreased from 20.8 to 16.7 capillary loops (P=0.015).
Proteinuria developed or increased in six patients during telatinib treatment.
Conclusion
The increase in blood pressure observed in the treatment with telatinib, an angiogenesis inhibitor, may be caused by functional or structural rarefaction.
Introduction
Dysregulated signaling through the vascular endothelial growth factor (VEGF)/VEGF re- ceptor-2 (VEGFR-2) pathway mediates neoangiogenesis and thereby promotes tumor development and metastasis.1,2 Overexpression of VEGF is common in solid tumors and has been associated with poor prognosis3. Furthermore, the overexpression or increased activation of VEGFR-2 has been associated with a poor prognosis in solid tumors.4,5 In preclinical models, inhibition of the tyrosine kinase activity of the VEGFR-2 blocks angio- genesis and inhibits the growth of tumors.6
Hypertension is a commonly reported side effect in trials with inhibitors of VEGF/
VEGFR-2 signaling, like bevacizumab and sunitinib.7–12 The mechanisms leading to this increase in blood pressure during antiangiogenic therapy have not been elucidated. Pro- posed mechanisms include reduced formation of nitric oxide (NO) by endothelial cells, a reduced responsiveness of vascular smooth muscle cells to NO, an increased production of or reaction to vasoconstricting stimuli, a reduced compliance and distensibility of the vascular wall, and microvascular rarefaction.13–15 Because microvessels (arterioles and capillaries) are a major contributor to total peripheral vascular resistance, functional rarefaction (a decrease in perfused microvessels) or anatomic rarefaction (a reduction in capillary density) may play an important role in the development of hypertension.
We hypothesized that systemic inhibition of VEGF impairs vascular function and causes rarefaction, which then leads to the development of hypertension in patients treated with antiangiogenic agents.
Materials and methods
This study was conducted on a subset of patients enrolled into an open-label, nonran- domized, two-center, phase I dose-escalating study of oral telatinib (Bay 57-9352).16 The purpose of this study was to search for possible mechanisms that cause hypertension in patients treated with antiangiogenic therapy and to confirm our hypothesis that sys- temic inhibition of VEGF inhibits vascular function and causes rarefaction.
Patients
Patients with advanced solid tumors with no standard treatment available were eligible for study participation. Inclusion criteria were age of 18 y or older; WHO performance status of 0 to 2; life expectancy of at least 12 wk; and adequate bone marrow, liver, and renal function. Exclusion criteria were history of cardiac disease; history of HIV,
hepatitis B, or hepatitis C infection; active clinically serious infection; serious nonheal- ing wound, ulcer, or bone fracture; symptomatic metastatic brain or meningeal tumors;
pregnancy or breast feeding; treatment with any anticancer agent or investigational drug 4 wk before the first dose; antiangiogenic therapies/VEGFR-2 inhibitors before en- rollment.
The side-study was conducted on patients that were treated in the Leiden University Medical Center. The study protocol was approved by the Medical Ethical Committee of the Leiden University Medical Center. All patients gave written informed consent.
Intervention
Telatinib (Bay 57-9352) is an orally active, small molecule inhibitor of the VEGFR-2 (IC50 in biochemical assay, 6 nmol/L), VEGFR-3 (IC50, 4 nmol/L) tyrosine kinases, and the growth factors receptors platelet-derived growth factor receptor-α (IC50, 15 nmol/L) and c-Kit (IC50, 1 nmol/L). Telatinib was continuously given once daily or twice daily in an oral formulation as solution or tablet. Patients were divided into cohorts with escalating doses. Therapy continued until progressive disease, unacceptable toxicity, death, con- sent withdrawal, or withdrawal from study at the discretion of the investigator. Telatinib was provided by Bayer Pharmaceuticals Corporation.
We assessed blood pressure, vascular function, and structure variables at baseline, and after 5 wk of treatment, in addition to regular evaluation of variables for safety, pharmacokinetics, and efficacy.
Hemodynamic, vascular function, and vascular structure variables and proteinuria
Blood pressure, flow-mediated dilation (FMD), nitroglycerin-mediated dilation (NMD), aortic pulse wave velocity (PWV), skin blood flux with laser doppler flow, and capillary density with sidestream dark field (SDF) imaging were assessed at baseline and after 5wk of treatment with telatinib. All measurements were done by the same experienced investigator, in the morning, in a quiet, temperature-controlled room.
Peripheral blood pressure measurements were also done at every weekly visit to the outpatient clinic.
Peripheral blood pressure
Peripheral blood pressure measurements at baseline and at the 5-wk visit were done after 15 min rest, measuring thrice in a supine position with 5-min intervals, using an automatic device (Datex-Ohmeda S/5 Light Monitor, Datex-Ohmeda, Inc.) with the cuff
placed at the brachial artery. For statistical analysis, we used the mean of three consecu- tive measurements. Peripheral blood pressure measurements at the weekly visit to the outpatient clinic were done by the treating physician, using an aneroid sphygmoma- nometer (Maxi-Stabil 3, Speidel & Keller, Welch Allyn) with the auscultatory method.
Central blood pressure
Application tonometry of the brachial and external carotid artery (SphygmoCor SCOR- PVx device, AtCor) was done. The mean of the three peripheral blood pressure measure- ments was used to calculate central aortic pressure.17
Aortic pulse wave velocity
Measurements were done at the right carotid and femoral arteries using standard blood pressure transducers (SphygmoCor SCOR-PVx device, AtCor) with simultaneous electro- graphic gating. This enabled the base of the pressure wave to be recorded and the time delay between the carotid and femoral waves to be calculated. The distance between the two sites was measured. PWV was defined as the distance traveled by the pressure waves divided by the time delay.
Flow mediated dilation
The FMD measurements were done in a quiet, temperature-controlled room. Postisch- emic vasodilator responses in the brachial artery were measured using a Wall Track System (WTS 2, Pie Medical). This system consists of a standard 7.5-MHz linear array ultrasound transducer connected to a PC equipped with a data acquisition board and software. Subjects were investigated in a supine position, and three ECG leads were attached. Ischemia was induced in the forearm by inflation of a blood pressure cuff just below the elbow of the right arm for 5 min. After deflation of the cuff, changes in brachial artery wall diameter were measured every 20 s for 4 min. WTS measurements were stored and analyzed off line using WTS software. FMD was expressed as percent- age change in brachial artery diameter after ischemia.
NMD
NMD was assessed in the same way as FMD, with the exception that 0.4 mg of nitro- glycerin were given sublingually, instead of cuff inflation and deflation, before measure- ments were started.
Laser Doppler flowmetry
Forearm skin blood flux was measured using laser Doppler flowmetry (Periflux PF4001, Perimed; wavelength, 782 nm) before and during forearm postischemic hyperemia.18
Flows were recorded by the Perisoft program, with the time constant set at 3 s down- stream from a broadband filter (12 MHz). Results were reported as arbitrary flow units (10 mV). The percentage of change in arbitrary units from baseline (before ischemia) to maximal flow in the postischemic hyperemic phase was reported.
Capillary density measurements with SDF imaging
Patients were situated in a supine position with the investigator at the head side of the bed. An SDF hand-held device (MicroScan Video Microscope System, MicroVision Medi- cal) was introduced into the open mouth and gently pushed to the mucosal surface of the inner lip. SDF imaging consists of a light guide surrounded by light-emitting diodes that emit green light (540 F 50 nm) which penetrates the tissue and directly illuminates the tissue microcirculation. The SDF technique and the technique of its precessor orthog- onal spectral polarization imaging are described in detail in previous publications.19,20
Images of the mucosal microcirculation were projected on a computer screen. The final on-screen magnification of the images obtained with the SDF imaging device was 325 times original. When images of satisfying quality were seen, video images of at least 30 s were obtained. Images were obtained from four different lip quadrants (mucosal readings of the left and right upper inner lip quadrant and the left and right lower inner lip quadrant) using the SDF probe. From every quadrant, at least three 30-s video images were obtained. Video images were stored on digital videotape in .avi format.
Off line, at least five still frames of each quadrant were captured from these video images. The number of capillary loops per frame was counted. Capillary density for each frame was expressed as the mean number of capillary loops per mm2. The mean capillary density per lip quadrant and total lip was calculated.
All measurements were done by one technician, not blinded to the time point in treatment of the patients. Off-line analysis (counting of the number of capillary loops) was done by two observers, who were blinded to the time point in treatment of the patients.
Whereas the technique has not been used very frequently in the measurement of mi- crocirculation of the mucosal surface of the inner lip, additional quality measurements were done. In 10 healthy volunteers, no difference in capillary density was observed be- tween the different lip quadrants. The reproducibility of the SDF technique to determine capillary density was moderate to high, showing a coefficient of variation of 4.6%.
Proteinuria
Urinalysis, measured by dipstick, was done weekly in all patients to monitor proteinuria.
Proteinuria was recorded according to the National Cancer Institute Common Toxicity Cri- teria version 3.0. Grade 1 is defined as 1+ by dipstick, grade 2 as 2+ or 3+ by dipstick,
grade 3 as 4+ by dipstick, and grade 4 as nephrotic syndrome. We report the development of proteinuria (grade 0 before treatment increasing to grade >0 during treatment) and the worsening of proteinuria (increase of proteinuria by z1 grade compared with baseline).
Pharmacokinetic analysis
Serial blood samples were collected for pharmacokinetic analysis on days 1 and 14 of cycle 1. Telatinib plasma concentrations were analyzed by a noncompartmental method using the KINCALC software package, Bayer AG, version 2.33 or higher. Peak plasma level (Cmax), area under the concentration-time curve [AUC(0-tn)], were calculated.
Statistical analysis
Continuous variables are presented as mean values ± SD and categorical variables as frequencies (percentages), unless otherwise stated. Comparisons between variables at baseline and after 5 wk were done with paired Student’s t-tests and were two-sided, with a level of significance of α = 0.05. For skin blood flux and capillary density, the Wilcoxon signed-rank test was used. The relationship between blood pressure, vascular function and structure variables, and telatinib daily dose and telatinib pharmacokinetic variables [Cmax and AUC(0-tn)] was investigated by correlation analysis. Correlation analy- sis was done using Pearson’s and Spearman’s correlation coefficients where appropriate.
Correlations with proteinuria were done using an armitage test for trend. For correlation purposes proteinuria was reported as presence of new proteinuria or increase in existing proteinuria (yes or no). All analyses were done using SPSS version 12.01 (SPSS).
Results
Eighteen of 33 patients treated in our hospital were included in this side study. Reasons for exclusion were vaso-active hormone producing adrenal carcinoma (n = 3), absence of measurements for logistics reasons between June and December 2005 (n = 7), ab- sence of measurements at 5 weeks due to early drop out for early progressive disease (n = 2), anatomic anomaly of the arm (n = 1), absence of appropriate drug compliance (supported by pharmacokinetic data; n = 1), and failure to upheld appointment baseline visit (n = 1). NMD measurements were not done in two patients; both had a preexisting headache and refused sublingual nitroglycerin administration.
Baseline demographics and patient characteristics of the 18 patients included in this study are listed in Table 1. Patients received the following starting doses of Bay 57-9352:
patient 1, 20 mg solution once daily; patients 2 to 3, 75 mg (25 mg tablets) once daily;
patients 4 to 5, 150 mg (150 mg tablets) twice daily; patients 6 to 9, 300 mg (150 mg tablets) twice daily; patient 10, 600 mg (150 mg tablets) twice daily; and patients 11 to 18, 900 mg (150 mg tablets) twice daily.
Blood pressure results
Both peripheral systolic blood pressure and peripheral diastolic blood pressure increased in 14 of 18 patients (78%) after 5 weeks treatment with telatinib compared with baseline Table 1. Baseline demographics and patient characteristics
Baseline characteristics
N 18
Male gender 9 (50) Age, y (range) 55 (22-76) Additional cardiovascular risk factors
Body mass index, kg/m2 (range) 24.7 (20.5-29.7) Nicotine abuse, in past or present 5 (28) History of cardiovascular disease 0 (0) History of hypertension 1 (6) Renal impairment (creatinine > ULN) 5 (28) WHO performance scale
0 4 (22)
1 14 (78)
Prior treatment
Surgery 13 (72)
Chemotherapy 17 (94) Radiotherapy 8 (44) Blood pressure lowering drugs at entry 2 (11) Tumor type
Anal carcinoma 1 (6) Carcinoid tumor 1 (6) Cholangiocarcinoma 1 (6) Colorectal carcinoma 3 (17) Esophageal carcinoma 1 (6) Ovarian carcinoma 3 (17) Prostatic carcinoma 1 (6) Renal cell carcinoma 1 (6) Soft tissue sarcoma 5 (28) Urothelial cell carcinoma 1 (6)
NOTE: Data are presented as n (%) unless otherwise specified. Abbreviation: ULN, upper limit of normal.
Fig. 1. Blood pressure (A), skin blood flux (C), and capillary density (D) results at baseline and after 5 wk of treatment with telatinib. B, mean systolic blood pressure (continuous line) and mean diastolic blood pressure (dashed line) before treatment, weekly during treatment, and after discontinuation of telatinib treatment. A horizontal dashed line was added at baseline systolic blood pressure and baseline diastolic blood pressure for facilitation of reading. Left from the vertical line blood pres- sures measured in the first 84 d of treatment. Right from the vertical line blood pressures measured 7 and 28 d after discontinuation of treatment. pSBP, peripheral systolic blood pressure; pDBP, pe- ripheral diastolic blood pressure; cSBP, central systolic blood pressure; cDBP, central diastolic blood pressure; LDF, laser doppler flow; %AU, percentage of change from baseline in arbitrary units; n, number.
1A 1B
70 80 90 100 110 120 130 140 150
pSBP pDBP cSBP cDBP
Blood pressure (mm Hg)
After 5 weeks
110 120 130 140 150
0 14 28 42 56 70 84 98 112 Days
SBP (mm Hg)
67 73 79 85 91
DBP (mm Hg)
+7 +28
1C
1D
0 200 400 600 800 1000 1200 1400 1600
LDF
Skin blood flux (%AU)
Baseline After 5 weeks
0 5 10 15 20 25
SDF
Capillary density (n)
Baseline After 5 weeks Baseline After 5 weeks
values. The mean peripheral systolic blood pressure significantly increased from 132.2 to 138.8 mm Hg (P = 0.009), and the mean peripheral diastolic blood pressure values increased from 83.1 to 87.8 mm Hg (P = 0.016; Table 2; Fig. 1A). The increase in central systolic blood pressure (4.3 mm Hg) was not statistically significant (P = 0.106). Both peripheral and central pulse pressure showed no change after 5 weeks of treatment.
Mean peripheral blood pressures measured at the weekly visits showed a similar increase in both systolic and diastolic blood pressure (Fig. 1B). Blood pressure results for
Table 2.
A. Hemodynamic and vascular function/structure variables at baseline and after 5 wk of treatment with telatinib
Baseline values
After 5 wk treatment
Change ± SD 95% Confidence interval
P
pSBP (mm Hg) 132.2 138.8 +6.6 ± 9.5 (1.9 to 11.3) 0.009*
pDBP (mm Hg) 83.1 87.8 +4.7 ± 7.4 (1.0 to 8.4) 0.016*
cSBP (mm Hg) 129.9 134.2 +4.3 ± 10.9 (-1.0 to 9.8) 0.106 cDBP (mm Hg) 82.9 87.5 +4.6 ± 7.8 (0.7 to 8.4) 0.024*
MAP (mm Hg) 102.5 107.6 +5.1 ± 7.2 (1.5 to 8.7) 0.008*
pPP (mm Hg) 54.3 57.1 +2.8 ± 12.9 (-3.6 to 9.2) 0.369 cPP (mm Hg) 47.0 46.8 –0.2 ± 10.2 (-5.2 to 4.9) 0.946 FMD (%) 6.0 3.9 –2.1 ± 2.6 (0.8 to 3.5) 0.003*
NMD (%) 17.0 11.9 –5.1 ± 4.1 (2.9 to 7.3) 0.001*
PWV (m/s) 8.5 9.7 +1.2 ± 0.8 (0.8 to 1.7) 0.001*
Skin blood flow (%AU) 1091.5 558.7 –532.8 ± 362.0 (-912.7 to -152.9) 0.015*
Capillary density (n) 20.8 16.7 –4.1 ± 3.3 (-7.2 to -1.1) 0.015*
B. Individual blood pressure data before treatment, during treatment, and after discon- tinuation of telatinib treatment
Pt Systolic blood pressure, d
0 7 14 21 28 35 42 49 56 63 70 77 84 +7 +28
1 110 105 110 115 115 110 130 120 115 120 115 110
2 115 115 120 120 125 120 115 130 120
3 130 160a 135 140 150 128 150 180a 145 145 135 4 130 125 120 138 120 125 125
5 115 120 125 120 120 125 130 110
6 145 150 145 155a 140 140 135 130 160a 150 120
7 110 100 120 125 110 110 120 125 105 110
8 130 140 150 150 160 160 130 130 125 140 110 9 105 130 130 140 125 130 110
10 130 120 126 140 135 120 140 130 135 130 140 100 11 120 120 130 130 135 120
12 140 130 135 130 125 170a 130 160 149 163 150 110 13 120 125 150 140 156a 140 150 130 130 130
14 125 143 130 130 112 120
15 120 125 110 120 120 135 120 120
16 135 130 150 145 130 110 118
17 130 125 130 135 120 128 125
18 125 140 145 150 125 130 125 140 135 105 130 ongoing
the individual patients are reported in Table 2B. Results for the first 84 days on treatment are reported. The number of patients on telatinib treatment after 84 days was too small for reliable results to be reported (n = 7). None of the seven patients remaining on study medication after 84 days developed a new increase in blood pressure. In all patients, the blood pressure values returned to baseline within 4 weeks after the discontinuation of the telatinib.
One patient received antihypertensive medication before start of treatment (thia- zide diuretic). Four additional patients were started on antihypertensive treatment: one patient receiving 600 mg telatinib daily and three patients receiving 1800 mg daily.
Antihypertensive medication consisted of a thiazide diuretic in one patient, a calcium antagonist in one patient, and an ACE inhibitor in two patients.
Pt Diastolic blood pressure, d
0 7 14 21 28 35 42 49 56 63 70 77 84 +7 +28
1 60 60 55 70 55 70 65 60 60 70 55 70
2 70 80 80 80 80 80 80 80 80
3 75 80 75 80 70 72 70 80 80 70 75
4 85 90 90 85 65 60 70
5 75 80 75 85 80 75 80 70
6 85 85 85 85 80 90 85 85 90 90 80
7 70 70 75 85 85 80 80 80 70 70
8 75 70 80 90 90 89 85 75 80 80 60
9 70 90 85 90 80 80 70
10 75 80 81 85 80 85 70 85 80 75 65 70
11 75 75 80 85 85 80
12 80 80 85 80 80 102a 90 100 100 98 85 75
13 70 80 89 85 97 90 90 80 80 75
14 80 79 85 80 78 75
15 75 80 70 70 80 80 80 80
16 85 90 110 90 75 70 77
17 85 80 85 90 80 74 80
18 80 85 85 90 85 85 80 90 90 70 80 ongoing
NOTE: Data in italics indicate antihypertensive medication started.
Abbreviations: pSBP, peripheral systolic blood pressure; pDBP, peripheral diastolic blood pressure; cSBP, central systolic blood pressure; cDBP, central diastolic blood pressure; MAP, mean arterial pressure; pPP, peripheral pulse pressure; cPP, carotid pulse pressure; %AU, percentage of change from baseline in arbitrary units; n, number.
*P < 0.05.
aNo antihypertensive treatment started, regardless of protocol.
B. Individual blood pressure data before treatment, during treatment, and after discon- tinuation of telatinib treatment
Vascular function and vascular structure assessments
FMD decreased from baseline in 15 of 18 patients (83%) after 5 weeks treatment with telatinib. At 5 weeks, the mean decrease in FMD, compared with baseline, was statisti- cally significant, from 6.0% to 3.9% (P = 0.003; Table 2). After 5 weeks of treatment, NMD decreased in 94% of patients. The mean change in NMD from 17.0% at baseline to 11.9% after 5 weeks was statistically significant (P = 0.001; Table 2). An increase in PWV was seen in 17 of 18 patients (94%). Mean PWV significantly increased from 8.5m/s at baseline to 9.7 m/s after 5 weeks treatment (P = 0.001; Table 2). Mean forearm skin blood Fig. 2. SDF images demonstrating visible capillary loops of a representative patient. A, at baseline.
B, after 5wk of telatinib treatment. Black arrows, larger venules; white arrows, individual superficial capillary loops.
A
B
flux decreased significantly (-532.8 %AU, P = 0.015; Table 2). SDF imaging was done in seven patients. In all of the patients, the number of capillary loops markedly decreased after 5 weeks of treatment (Figs. 1 and 2; Table 2). Capillary density, the mean number of capillary loops per image, decreased from 20.8 at baseline to 16.7 after 5 weeks treat- ment with telatinib (P = 0.015).
Proteinuria
In four patients, proteinuria was reported at baseline, grade 1 proteinuria in one patient, and grade proteinuria in three patients. Proteinuria increased in one of those patients from grade 1 to grade 2. Five patients developed new onset proteinuria during telati- nib treatment: grade 1 in three patients and grade 2 in two patients. Five of these six patients with new onset or increasing proteinuria were receiving the highest dose of telatinib at 1,800 mg daily. After discontinuation of treatment in three of six patients, the proteinuria returned to normal. For the other three patients, no data for proteinuria after discontinuation of telatinib were available. In two of the six patients with new Table 3. Telatinib daily dose and pharmacokinetic variables [Cmax and AUC(0-tn)]
Patient Daily dose (mg)
Cycle 1, day 1 Cycle 1, day 14 Cmax, mg/L AUC(0-tn), mg h/L Cmax, mg/L AUC(0-tn), mg h/L
1 20 0.2061 0.5284 0.1658 0.9628
2 75 0.2927 1.7464 0.1888 1.8779
3 75 0.3734 1.4246 0.4526 1.6941
4 300 0.0675 0.4141 0.1822 1.7680
5 300 0.0935 0.7527 0.1355 1.0164
6 600 1.2678 3.4588 1.1915 5.9823
7 600 0.1250 0.4504 0.6493 3.3407
8 600 0.1888 1.1649 0.2897 2.3776
9 600 1.2809 8.7848 1.4486 10.3795
10 1200 2.1691 16.7094 1.6995 16.4708
11 1800 0.4298 2.4610 1.7637 5.2292
12 1800 1.0484 7.0520 1.1216 7.3369
13 1800 0.2856 3.0094 0.2229 1.9701
14 1800 0.0552 0.8416 0.0969 0.8832
15 1800 0.2918 2.7700 0.8145 6.7397
16 1800 1.2599 3.4356 0.5728 3.1803
17 1800 1.6730 9.7474 2.6011 12.2049
18 1800 0.4515 2.9511 0.7626 6.2329
or increasing proteinuria, an increase in blood pressure above 150 mm Hg systolic or above 100 mm Hg diastolic was reported. These two patients were treated with an ACE inhibitor, resulting in disappearance of the proteinuria. The other four patients were not treated for the proteinuria.
Pharmacokinetic analysis and correlations
Telatinib pharmacokinetic variables [Cmax and AUC(0-tn)] are shown in Table 3. There was no correlation between either blood pressures or vascular function/structure variables and daily dose of telatinib or telatinib pharmacokinetic variables [Cmax and AUC(0-tn)]. No correlation between development or increase of proteinuria and blood pressure mea- surements or any of the other variables was seen. However, there was positive correla- tion between daily dose of telatinib and proteinuria (linear-by-linear association, 5.0;
P =0.025). All patients with SDF measurements done received 1,800 mg of telatinib a day. No correlation between SDF results and daily dose could therefore be calculated.
Discussion
We studied the effects of telatinib, a tyrosine kinase inhibitor and potent inhibitor of angiogenesis, on the vasculature to determine a mechanism by which small molecule angiogenesis inhibitors cause an increase in blood pressure. The rarefaction (reduction in capillary density) and change in microvascular characteristics observed in this study provide a plausible mechanism for the increase in systolic and diastolic blood pressure.
Telatinib caused a significant decrease in endothelium-dependent and endothelium- independent vasodilation. VEGF inhibition by itself decreases NO synthesis, which pro- motes vasoconstriction, increases peripheral resistance, and therefore can induce an increase in blood pressure.21–24 It remains unclear whether the key problem is impaired NO synthesis, the change in capillary structure leading to impaired NO vascular smooth muscle cell responsiveness, or a combination of both. Aortic pulse wave velocity is a vari- able for vascular stiffness, a which is known to increase with age, and is an independent predictor of cardiovascular risk and all-cause mortality in renal disease, hypertensive patients, and patients with diabetes mellitus.25–27 We observed a significant increase in PWV, which correlated with the increase in mean arterial pressure. Although blood pres- sure is a known independent determinant of pulse wave velocity, it cannot be excluded that inhibition of angiogenesis has a direct effect on stiffness of the arterial tree.28 In a subgroup of patients, we did SDF imaging to visualize a the microvessels in the buccal mucosa. All patients showed a reduction in the number of mucosal capillaries (rarefac- tion) during antiangiogenic treatment. Vessels smaller than 150 Pm in diameter are the
most important segment of the vascular bed to regulate blood flow and blood pres- sure.29,30 A reduction in the number of (functional) arterioles and capillaries leads to increased peripheral vascular resistance and blood pressure. Rarefaction is a consistent finding in patients with hypertension,30–32 and it is also reported in normotensive young adults with a genetic predisposition to high blood pressure.33 Blocking the growth of capillaries by VEGFR inhibitors and other angiogenesis inhibitors might lead to the same results even in subjects that are not predisposed to the development of hypertension.
Whether the observed rarefaction is structural (disappearance of capillaries) or func- tional (i.e., nonperfused existing capillaries) is unclear, as visualization of microvessels based upon the SDF technique depends on perfusion of these vessels. Although the rapid normalization of blood pressure within weeks and reversal in proteinuria in some patients after discontinuation of telatinib may indicate improvement in functional rar- efaction, this is more likely in functional then structural rarefaction. It remains uncertain whether the changes in microvessel architecture are reversible upon discontinuation of the treatment. While capillary density measurements were done in only seven patients, one should be careful with the interpretation of these results. These results have to be confirmed in a larger patient sample.
The exact mechanism by which telatinib leads to rarefaction and hypertension is unclear. Telatinib is a small molecule tyrosine kinase inhibitor, blocking the ATP-binding site of the VEGFR-2, VEGFR-3, platelet-derived growth factor receptor-α, and c-Kit re- ceptors. Platelet-derived growth factor and c-Kit receptor activation result in activation of pathways that, for a large part, are also activated by VEGFR-2. However, hyperten- sion is rarely seen in the treatment with platelet-derived growth factor and c-Kit inhibi- tors, such as imatinib and nilotinib.34,35 In contrast, selective inhibitors of VEGF/VEG- FR-2 signaling, such as sunitinib or bevacizumab, frequently cause hypertension.7–10 The increase in blood pressure is therefore most likely caused by the inhibition of the VEGFR signaling. However, we cannot rule out that c-KIT or platelet-derived growth factor inhibition has a role in mediating the blood pressure changes or changes in any of the other measured variables. A recently published preclinical observation suggests that VEGF signaling is required for vascular homeostasis.36 Our findings could be the clinical proof of that concept.
Our study has several limitations. First, the study was set up as a side-study of a phase I dose-finding study. Therefore, different dosages of telatinib were used by our patients. However, there was no correlation between changes on blood pressure, vascu- lar structure/function variables, capillary density, and daily dose of telatinib or telatinib exposure. Even in the patients with lower doses of telatinib, significant changes in all measured variables were seen. Second, due to the small number of patients it was not possible to reliably quantitate capillary characteristics, such as length, diameter size, and
tortuosity. Third, no control group was measured and distinction between treatment and placebo effects is therefore not clear. Fourth, no vascular measurements were done after discontinuation of treatment. Whereas all patients had advanced tumors with a low life expectancy, we chose not to burden these patients with additional measure- ments after cessation of the study drug. Finally, the temporal relationship between rar- efaction and hypertension is unclear. Therefore, future studies, in larger patient samples, with measurements before, during, and after treatment are necessary.
In the most extensively studied VEGF inhibitor bevacizumab, the increase in blood pressure is dose dependent.13 We did not observe this in our study. This could have been due to the small study size. In addition, the start of antihypertensive medication may have masked a correlation between blood pressure and daily dose of telatinib. However, the development or increase of proteinuria was dose dependent. Another explanation for the sole dose dependency for proteinuria is that telatinib may have an effect on glomerular endothelial cells, which is independent of blood pressure and independently caused by the VEGF blockade.37–40
In conclusion, we report that 5 weeks of treatment with a small molecule tyrosine kinase inhibitor, blocking VEGFR-2 and VEGFR-3, results in a significant increase in both systolic and diastolic blood pressure. The reduction in capillary density and microvascu- lar flow, associated with a reduced vasodilatory capacity, may suggest that rarefaction is a mechanism that underlies the increase in blood pressure induced by telatinib and pos- sibly other antiangiogenic agents. Further research in larger patient samples is needed to confirm this hypothesis.
References
1. Pisacane AM, Risio M. VEGF and VEGFR-2 immunohistochemistry in human melanocytic naevi and cutane- ous melanomas. Melanoma Res 2005;15:39-43.
2. Hicklin DJ, Ellis LM. Role of the vascular endothelial growth factor pathway in tumor growth and angiogen- esis. J Clin Oncol 2005;23:1011-27.
3. Raben D, Helfrich B. Angiogenesis inhibitors: a rational strategy for radiosensitization in the treatment of non-small-cell lung cancer? Clin Lung Cancer 2004;6:48-57.
4. Giatromanolaki A, Koukourakis MI, Turley H, Sivridis E, Harris AL, Gatter KC. Phosphorylated KDR expres- sion in endometrial cancer cells relates to HIF1a/VEGF pathway and unfavourable prognosis. Mod Pathol 2006;19:701-7.
5. Xia G, Kumar SR, Hawes D, et al. Expression and significance of vascular endothelial growth factor receptor 2 in bladder cancer. J Urol 2006;175:1245–52.
6. Amino N, Ideyama Y, Yamano M, et al. YM-359445, an orally bioavailable vascular endothelial growth factor receptor-2 tyrosine kinase inhibitor, has highly potent antitumor activity against established tumors. Clin Cancer Res 2006;12:1630-8.
7. Verheul HM, Pinedo HM. Inhibition of angiogenesis in cancer patients. Expert Opin Emerg Drugs 2005;10:
403-12.
8. Sane DC, Anton L, Brosnihan KB. Angiogenic growth factors and hypertension. Angiogenesis 2004; 7:193- 201.
9. Veronese ML, Mosenkis A, Flaherty KT, et al. Mechanisms of hypertension associated with BAY 43-9006. J Clin Oncol 2006;24:1363–9.
10. Hurwitz H, Fehrenbacher L, Novotny W, et al. Bevacizumab plus irinotecan, fluorouracil, and leucovorin for metastatic colorectal cancer. N Engl J Med 2004; 350:2335-42.
11. Hurwitz HI, Fehrenbacher L, Hainsworth JD, et al. Bevacizumab in combination with fluorouracil and leu- covorin: an active regimen for first-line metastatic colorectal cancer. J Clin Oncol 2005;23:3502–8.
12. Motzer RJ, Hutson TE, Tomczak P, et al. Sunitinib versus interferon a in metastatic renal-cell carcinoma. N Engl J Med 2007;356:115-24.
13. Mourad JJ, des GG, Debbabi H, Levy BI. Blood pressure rise following angiogenesis inhibition by bevaci- zumab. A crucial role for microcirculation. Ann Oncol 2008;19:927-34.
14. Kamba T, McDonald DM. Mechanisms of adverse effects of anti-VEGF therapy for cancer. Br J Cancer 2007;96:1788– 95.
15. Verheul HM, Pinedo HM. Possible molecular mechanisms involved in the toxicity of angiogenesis inhibition.
Nat Rev Cancer 2007;7:475-85.
16. Gelderblom H, Verweij J, Steeghs N, et al. Phase I, safety, pharmacokinetic and biomarker study of telatinib (BAY 57-9352), an oral VEGFR-2 inhibitor, in a continous schedule in patients with advanced solid tumors.
Eur J Cancer Suppl 2007;4:25.
17. Van Bortel LM, Balkestein EJ, van Der Heijden-Spek JJ, et al. Non-invasive assessment of local arterial pulse pressure: comparison of applanation tonometry and echo-tracking. J Hypertens 2001;19:1037–44.
18. Cracowski JL, Minson CT, Salvat-Melis M, Halliwill JR. Methodological issues in the assessment of skin micro- vascular endothelial function in humans. Trends Pharmacol Sci 2006;27:503-8.
19. Groner W, Winkelman JW, Harris AG, et al. Orthogonal polarization spectral imaging: a new method for study of themicrocirculation. Nat Med1999;5:1209 –12.
20. Ince C. The microcirculation is the motor of sepsis. Crit Care 2005;9 Suppl 4:S13-9.
21. Meredith IT, Currie KE, Anderson TJ, Roddy MA, Ganz P, Creager MA. Postischemic vasodilation in human forearm is dependent on endothelium-derived nitric oxide. Am J Physiol 1996;270:H1435-40.
22. Joannides R, HaefeliWE, Linder L, et al. Nitric oxide is responsible for flow-dependent dilatation of human peripheral conduit arteries in vivo.Circulation1995;91: 1314-9.
23. Esper RJ, Nordaby RA, Vilarino JO, Paragano A, Cacharron JL, Machado RA. Endothelial dysfunction: a com- prehensive appraisal. Cardiovasc Diabetol 2006;5:4.
24. Ducharme A, Dupuis J, McNicoll S, Harel F, Tardif JC. Comparison of nitroglycerin lingual spray and sublin- gual tablet on time of onset and duration of brachial artery vasodilation in normal subjects. Am J Cardiol 1999;84:952– 4.
25. Khoshdel AR, Thakkinstian A, Carney SL, Attia J. Estimation of an age-specific reference interval for pulse wave velocity: a meta-analysis. J Hypertens 2006;24:1231-7.
26. Boutouyrie P, Tropeano AI, Asmar R, et al. Aortic stiffness is an independent predictor of primary coronary events in hypertensive patients: a longitudinal study. Hypertension 2002;39:10–5.
27. Laurent S, Boutouyrie P, Asmar R, et al. Aortic stiffness is an independent predictor of all-cause and cardio- vascular mortality in hypertensive patients. Hypertension 2001;37:1236–41.
28. Stefanadis C, Vlachopoulos C, Karayannacos P, et al. Effect of vasa vasorum flow on structure and function of the aorta in experimental animals. Circulation 1995;91:2669 –78.
29. Koller A. Signaling pathways of mechanotransduction in arteriolar endothelium and smooth muscle cells inhypertension. Microcirculation 2002;9:277–94.
30. le Noble FA, Stassen FR, Hacking WJ, Struijker Boudier HA. Angiogenesis and hypertension. J Hypertens 1998;16:1563 –72.
31. Hutchins PM, Lynch CD, Cooney PT, Curseen KA. The microcirculation in experimental hypertension and ag- ing. Cardiovasc Res 1996;32:772–80.
32. Sullivan JM, Prewitt RL, Josephs JA. Attenuationof the microcirculation in young patients with high-output borderlinehypertension. Hypertension 1983;5:844–51.
33. Noon JP, Walker BR, Webb DJ, et al. Impaired microvascular dilatation and capillary rarefaction in young adults with a predisposition to high blood pressure. J Clin Invest 1997;99:1873-9.
34. Verweij J, Casali PG, Zalcberg J, et al. Progression-free survival in gastrointestinal stromal tumours with high- dose imatinib: randomised trial. Lancet 2004; 364:1127-34.
35. Kantarjian H, Giles F, Wunderle L, et al. Nilotinib in imatinib-resistant CML and Philadelphia chromosome- positive ALL. N Engl J Med2006;354:2542-51.
36. Lee S, Chen TT, Barber CL, et al. Autocrine VEGF signaling is required for vascular homeostasis. Cell 2007;130:691-703.
37. Zhu X, Wu S, Dahut WL, Parikh CR. Risks of proteinuria and hypertension with bevacizumab, an anti- body against vascular endothelial growth factor: systematic review and meta-analysis. Am J Kidney Dis 2007;49:186– 93.
38. Vuorela P, Helske S, Hornig C, Alitalo K, Weich H, Halmesmaki E. Amniotic fluid-soluble vascular endothelial growth factor receptor-1 in preeclampsia. Obstet Gynecol 2000;95:353-7.
39. Kincaid-Smith P. The renal lesion of preeclampsia revisited. Am J Kidney Dis 1991;17:144-8.
40. Eremina V, Sood M, Haigh J, et al. Glomerular-specific alterations of VEGF-A expression lead to distinct con- genital and acquired renal diseases. J Clin Invest 2003;111:707-16.
